Question

The net charge on a sulfide ion, $$S^{2}$$, is $$2$$. How does this ion obtain its charge?

Answer 1

A neutral sulfur atom gains $$2$$ electrons.
Explanation:
An ion can only be formed when a neutral atom gains or loses electrons.
Since electrons carry a negative charge, gaining electrons will result in the formation of a negatively charged ion, or anion. Similarly, losing electrons will result in the formation of a positively charged ion, or cation.
In your case, the sulfide anion, $$S^{2−}$$, carries a $$(2−)$$ negative charge, which can only mean that it gained electrons.
More specifically, it gained $$2$$ electrons. A neutral sulfur atom has an atomic number equal to $$16$$, which means that it has $$16$$ protons inside its nucleus and $$16$$ electrons surrounding its nucleus.
For each electron gained, the ion's overall charge decreases by $$1$$ unit, which further confirms the fact that the neutral sulfur atom gained $$2$$ electrons to get the $$(2−)$$ charge.